Nations grasp for response to N Korea nuclear test

South Korean conservative activists burn a mock North Korea's nuclear missile during an anti-North Korea rally in Seoul yesterday. North Korea announced it conducted a nuclear weapons test on Monday in defiance of worldwide appeals and threats of sanctions, sparking a furious reaction from Seoul, which called it an "unpardonable provocation". PHOTO: AFP

South Korea warned its military was remaining on high alert and even close ally China refused to rule out a harder line on the North after it carried out a nuclear test Monday despite calls to abandon its weapons programme.

But the secretive regime showed no sign of backing down, and an official warned it could fire a nuclear warhead unless it secured concessions from the United States, the nation it says is the reason for needing a nuclear weapon.

The five permanent members of the UN Security Council -- Britain, China, France, Russia and the United States, all nuclear powers -- were to meet later Tuesday to assess their options.

Japan's new Prime Minister Shinzo Abe pledged that his officially pacifist nation would not seek to develop the bomb itself after North Korea's test, but said the world had to take strong action.

Tokyo called for a so-called Chapter VII resolution from the UN Security Council leaving all options open -- including mandatory sanctions and, as a last resort, military action in the name of peace and security.

"North Korea's latest announcement is a serious challenge to Japan's security," the government spokesman, Chief Cabinet Secretary Yasuhisa Shiozaki, quoted Abe telling his cabinet.

"It also is a grave threat against the peace and security of East Asia and the international community," he said.

At an emergency Security Council session Monday, the United States proposed mandatory sanctions including inspections of all cargo in and out of North Korea, financial curbs and restrictions on goods that could have military uses.